/*
 * Copyright (C) Photon Vision.
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program.  If not, see <https://www.gnu.org/licenses/>.
 */

package org.photonvision.targeting;

import edu.wpi.first.util.protobuf.ProtobufSerializable;
import java.util.ArrayList;
import java.util.List;
import java.util.Optional;
import org.photonvision.common.dataflow.structures.PacketSerde;
import org.photonvision.struct.PhotonPipelineResultSerde;
import org.photonvision.targeting.proto.PhotonPipelineResultProto;
import org.photonvision.targeting.serde.PhotonStructSerializable;

/** Represents a pipeline result from a PhotonCamera. */
public class PhotonPipelineResult
        implements ProtobufSerializable, PhotonStructSerializable<PhotonPipelineResult> {
    private static boolean HAS_WARNED = false;

    // Frame capture metadata
    public PhotonPipelineMetadata metadata;

    // Targets to store.
    public List<PhotonTrackedTarget> targets = new ArrayList<>();

    // Multi-tag result
    public Optional<MultiTargetPNPResult> multitagResult;

    // HACK: Since we don't trust NT time sync, keep track of when we got this packet into robot code
    public long ntReceiveTimestampMicros = -1;

    /** Constructs an empty pipeline result. */
    public PhotonPipelineResult() {
        this(new PhotonPipelineMetadata(), List.of(), Optional.empty());
    }

    /**
     * Constructs a pipeline result.
     *
     * @param sequenceID The number of frames processed by this camera since boot
     * @param captureTimestamp The time, in uS in the coprocessor's timebase, that the coprocessor
     *     captured the image this result contains the targeting info of
     * @param publishTimestamp The time, in uS in the coprocessor's timebase, that the coprocessor
     *     published targeting info
     * @param targets The list of targets identified by the pipeline.
     */
    public PhotonPipelineResult(
            long sequenceID,
            long captureTimestamp,
            long publishTimestamp,
            List<PhotonTrackedTarget> targets) {
        this(
                new PhotonPipelineMetadata(captureTimestamp, publishTimestamp, sequenceID),
                targets,
                Optional.empty());
    }

    /**
     * Constructs a pipeline result.
     *
     * @param sequenceID The number of frames processed by this camera since boot
     * @param captureTimestamp The time, in uS in the coprocessor's timebase, that the coprocessor
     *     captured the image this result contains the targeting info of
     * @param publishTimestamp The time, in uS in the coprocessor's timebase, that the coprocessor
     *     published targeting info
     * @param targets The list of targets identified by the pipeline.
     * @param result Result from multi-target PNP.
     */
    public PhotonPipelineResult(
            long sequenceID,
            long captureTimestamp,
            long publishTimestamp,
            List<PhotonTrackedTarget> targets,
            Optional<MultiTargetPNPResult> result) {
        this(
                new PhotonPipelineMetadata(captureTimestamp, publishTimestamp, sequenceID),
                targets,
                result);
    }

    public PhotonPipelineResult(
            PhotonPipelineMetadata metadata,
            List<PhotonTrackedTarget> targets,
            Optional<MultiTargetPNPResult> result) {
        this.metadata = metadata;
        this.targets.addAll(targets);
        this.multitagResult = result;
    }

    /**
     * Returns the size of the packet needed to store this pipeline result.
     *
     * @return The size of the packet needed to store this pipeline result.
     */
    public int getPacketSize() {
        throw new RuntimeException("TODO");
        // return Double.BYTES // latency
        //         + 1 // target count
        //         + targets.size() * PhotonTrackedTarget.serde.getMaxByteSize()
        //         + MultiTargetPNPResult.serde.getMaxByteSize();
    }

    /**
     * Returns the best target in this pipeline result. If there are no targets, this method will
     * return null. The best target is determined by the target sort mode in the PhotonVision UI.
     *
     * @return The best target of the pipeline result.
     */
    public PhotonTrackedTarget getBestTarget() {
        if (!hasTargets() && !HAS_WARNED) {
            String errStr =
                    "This PhotonPipelineResult object has no targets associated with it! Please check hasTargets() "
                            + "before calling this method. For more information, please review the PhotonLib "
                            + "documentation at https://docs.photonvision.org";
            System.err.println(errStr);
            new Exception().printStackTrace();
            HAS_WARNED = true;
        }
        return hasTargets() ? targets.get(0) : null;
    }

    /**
     * Returns whether the pipeline has targets.
     *
     * @return Whether the pipeline has targets.
     */
    public boolean hasTargets() {
        return !targets.isEmpty();
    }

    /**
     * Returns a copy of the vector of targets.
     *
     * <p>Returned in the order set by target sort mode.
     *
     * @return A copy of the vector of targets.
     */
    public List<PhotonTrackedTarget> getTargets() {
        return new ArrayList<>(targets);
    }

    /**
     * Return the latest multi-target result. Be sure to check
     * getMultiTagResult().estimatedPose.isPresent before using the pose estimate!
     */
    public Optional<MultiTargetPNPResult> getMultiTagResult() {
        return multitagResult;
    }

    /**
     * Returns the estimated time the frame was taken, in the Received system's time base. This is
     * calculated as (NT Receive time (robot base) - (publish timestamp, coproc timebase - capture
     * timestamp, coproc timebase))
     *
     * @return The timestamp in seconds
     */
    public double getTimestampSeconds() {
        return (ntReceiveTimestampMicros
                        - (metadata.publishTimestampMicros - metadata.captureTimestampMicros))
                / 1e6;
    }

    /** The time that the robot Received this result, in the FPGA timebase. */
    public long getNtReceiveTimestampMicros() {
        return ntReceiveTimestampMicros;
    }

    /** Sets the FPGA timestamp this result was Received by robot code */
    public void setReceiveTimestampMicros(long timestampMicros) {
        this.ntReceiveTimestampMicros = timestampMicros;
    }

    @Override
    public String toString() {
        return "PhotonPipelineResult [metadata="
                + metadata
                + ", targets="
                + targets
                + ", multitagResult="
                + multitagResult
                + ", ntReceiveTimestampMicros="
                + ntReceiveTimestampMicros
                + "]";
    }

    @Override
    public int hashCode() {
        final int prime = 31;
        int result = 1;
        result = prime * result + ((metadata == null) ? 0 : metadata.hashCode());
        result = prime * result + ((targets == null) ? 0 : targets.hashCode());
        result = prime * result + ((multitagResult == null) ? 0 : multitagResult.hashCode());
        result = prime * result + (int) (ntReceiveTimestampMicros ^ (ntReceiveTimestampMicros >>> 32));
        return result;
    }

    @Override
    public boolean equals(Object obj) {
        if (this == obj) return true;
        if (obj == null) return false;
        if (getClass() != obj.getClass()) return false;
        PhotonPipelineResult other = (PhotonPipelineResult) obj;
        if (metadata == null) {
            if (other.metadata != null) return false;
        } else if (!metadata.equals(other.metadata)) return false;
        if (targets == null) {
            if (other.targets != null) return false;
        } else if (!targets.equals(other.targets)) return false;
        if (multitagResult == null) {
            if (other.multitagResult != null) return false;
        } else if (!multitagResult.equals(other.multitagResult)) return false;
        if (ntReceiveTimestampMicros != other.ntReceiveTimestampMicros) return false;
        return true;
    }

    public static final PhotonPipelineResultSerde photonStruct = new PhotonPipelineResultSerde();
    public static final PhotonPipelineResultProto proto = new PhotonPipelineResultProto();

    @Override
    public PacketSerde<PhotonPipelineResult> getSerde() {
        return photonStruct;
    }
}